1. Field of the Invention
This invention relates to a position responsive electrical switch, which includes a member which under the influence of gravity changes its position to open and close the contacts of the switch as the position of the switch is changed. The switch may be used in place of mercury switches which have been mounted on automobile hoods or trunk lids to complete or break a circuit to an electrical light when the hood or trunk lid is opened or closed respectively.
2. Description of Related Art Including Information Disclosed under Secs. 1.97-1.99
In the past, the position sensitive switches utilized to turn on and turn off the light upon the opening or closing of the hood or trunk lid of an automobile have included a quantity of mercury as the gravity responsive movable conductor. Wherein mercury is now considered a hazardous material, it is desirable to avoid its use, particularly in situations where it may be released into the environment without proper disposal. When mercury containing switches are used in an automobile, the probabilities of improper disposal of the mercury are quite high, both when it is necessary to replace a failed switch and when the automobile is scrapped. Even in a business directed to disposal of a large number of scrapped automobiles, the quantity of mercury involved does not make it economically attractive to separately process the small quantity of mercury found in the switches.
It is therefore an object of this invention to provide a position responsive switch which does not include mercury as one of its materials. It is a further object of this invention to provide a switch which is readily assembled from a minimum number of components, and which is reliable in its operation. It is a further object of this invention to provide a switch, the external contacts of which are positioned so as to be readily connected in a circuit to be controlled by the switch.
While the applicant's switch offers features not found in the prior art, others have recognized the environmental problem presented by mercury switches and have also provided gravity actuated switches wherein a conductive ball is mounted in a metal enclosure such that, in a predetermined position of the switch, the ball is engageable with an electrical contact to complete a circuit between the metal enclosure and the electrical contact. Switches which have been provided in the past are represented in the disclosures of the following U.S. patents:
______________________________________ U.S. Pat. No. INVENTOR ISSUE DATE ______________________________________ 3,729,602 Myers 04/24/73 3,733,447 Schneider, Jr. 05/15/73 4,042,796 Zink 08/16/77 4,467,154 Hill 08/21/84 4,513,183 Hill 04/23/85 4,956,629 Chen 09/11/90 ______________________________________
The Zink, the two Hill and the Chen patents all depict switches in which a conductive metal ball is placed within a conductive cylindrical housing and is movable from positions where it only contacts the metal sleeve, to a position wherein it not only contacts the metal sleeve, but also a conductive member centrally located with respect to the sleeve. However, the constructions of the switches in the above-mentioned patents are quite different from that of this invention. For instance, the Hill patents do not provide male or female connectors which are readily connected to mating connectors such as would be secured to the end of flexible conductors to which the switch is to be connected. Rather, as shown in FIG. 1 of the patent, a specially designed socket must be provided for the switch. The Zink patent reveals a switch structure considerably different from that of this invention. The contacts of the switch, which are normally closed, provide an indication of vibrations of the switch by momentarily opening the contacts of the switch.
The construction of the Chen switch is considerably more complex than that of the applicant's invention wherein it involves the assembly of a considerably greater number of components and the deformation, of both a rivet and a flange on a metallic housing. The Myers and the Schneider, Jr. patents are only included to show additional prior patents disclosing switches which include a ball as an actuating member.